Tomato flu: A mysterious catastrophic infection knocking at the door
Authors: Sovan Samanta, Jhimli Banerjee, Swarnali Das, Rubai Ahmed, Sandeep Kumar Dash
Journal: International Journal of Surgery (2023)

Dear Editor, While Kerala is dealing with the continuing coronavirus disease 2019 (COVID-19) pandemic and the threat of a monkeypox epidemic, the state has been put on high notice due to a sudden outbreak of unusual flu cases of a severe illness, which is commonly known as ‘tomato fever.’ Even though there have only been 80 confirmed cases of tomato fever in Kerala so far, other projections bring the effective figure to 100. Since May this year (2022), the Kollam district of Kerala, India has documented over 80 affected cases of children infected with the viral flu1,2. The authorities have a hunch that the recent increase in cases of tomato fever is due to the mass gathering after resumption of schools, which were closed during the COVID-19 pandemic and associated lockdown. In this regard, Karnataka’s Health Minister K. Sudhakar previously stated that reports of tomato fever in Kerala did not warrant concern1. However, it is interesting to note that, starting in the middle of May, Tamil Nadu has increased its medical security at all border posts in response to reports of tomato fever among children in Kerala3. As of May 11, 2022, this virus had affected a group of 80 children; all of them were from Kerala’s Kollam district (Fig. 1a). The important cities of Kollam district, Neduvathur, Anchal, and Aryankavu have been most severely impacted by the tomato fever4. Tomato fever is a rare type of viral fever that affects mostly children under the age of 5. Despite this, different myths about vegetables like tomatoes are rapidly propagated among Keralans. Many of these rumors claim that the edible tomato is to blame for this outbreak. But there is no scientific evidence linking tomato fever and edible tomato varieties. The name tomato fever may have arisen from the small, spherical blisters that appear on the body of a child and are frequently colored red2,5. The Keralan districts of Kottayam (Mudakayam, Varzur, and Kanirapally) and Pathinamtita were reported to be affected by this ailment in 2007. This frightening predicament was not the first to have indeed been exposed6. The illness manifests as skin discomfort and rashes. Children who have the illness report fatigue, joint discomfort, a high temperature, and body aches. Other symptoms include pigmentation of the hands, knees, and buttocks. Children who have the infection may also have nausea, vomiting, or diarrhoea. A runny nose, coughing, and sneezing are among common symptoms of the flu virus (Fig. 1b)2. The fact that the flu is brought on by a virus has been demonstrated beyond a reasonable doubt by researchers, but they have not yet been able to identify the specific family of viruses to which this virus belongs. It is worth noting that the illness somehow does not offer any significant threats towards one’s life, despite the fact that it is extremely infectious and spreadable. These infectious pathogens can linger in a child’s body for a considerable amount of time after an infection has cleared up7. Researchers focused intently on the preceding data from 2007 in Kerala, where over 2800 persons reported symptoms of tomato fever, which is spreading quickly in the areas of Mudakayam, Varzur, and Kanirapally in Kottayam and Pathinamtita districts (Fig. 1a). The fascinating observation is that individuals with a recent history of Chikungunya account for the majority of those infected8. On the basis of this earlier incidence, researchers or scientists are in doubt whether tomato fever is a virus-related illness or only a consequence of Chikungunya or Dengue fever4. Interestingly, in the middle of May 2022, 58 people died and were hospitalized in Kerala, owing to food poisoning. Many health professionals believe that this event has a strong association with tomato fever, although the real scientific explanation of this fatality has not been determined9. Another hypothesis emerged, according to which the fever and flu cases being reported in southern India are not caused by the tomato flu but rather by a virus similar to that which causes hand, foot, and mouth disease (HFMD). In this regard, virologist Dr Jacob John stated to BBC that the fever ought not to be referred to as tomato flu because it is actually a classic case of HFMD outbreak that has already been detected in Kerala10. Meanwhile, in Odisha, the Regional Medical Research Center in Bhubaneswar conducted tests on 36 samples following the emergence of identical symptoms, finding 26 to be positive. Nineteen of them, the majority of the group, were from Bhubaneswar. A lot of questions remained unanswered after this incident, including “What exactly where the symptoms that led to these problems?” As for Odisha’s positive cases, several experts have suggested that HFMD, rather than tomato fever, is the real source of this outbreak10,11. It has been determined beyond a reasonable doubt that the coxsackievirus in the United States is the infectious agent that causes HFMD12. In addition, another prior study revealed that a peculiar strain of enterovirus known as coxsackievirus A6 was the infectious agent that led to the outbreak of HFMD in Finland13. However, in the case of the Odisha outbreak, no scientific evidence was found or confirmed to demonstrate that this outbreak is a true instance of HFMD; hence, the conflict between tomato fever and HFMD remains. Despite this conflict, a new issue about the outbreak in Odisha is raised: is the causative agent (supposed to be tomato flu) beginning to travel outside of Kerala? Numerous sources indicate that this viral infection moved from Kerala to Odisha as a result of the frightening breakout in that state, although there is no conclusive evidence to support this assertion. On July 23, the director-general of the World Health Organization, Tedros Adhanom Ghebreyesus, rang the loudest warning of the organization to warn the severity of the global monkeypox outbreaks14. Over 5000 occurrences have already been documented in 52 countries and territories since the first cases were reported in the UK in early May15. These figures illustrate the virus’s virulent spread and high infectivity rate. The worrying issue is that Kerala reported the nation’s first three cases of monkeypox in India16. As a result, Kerala is now the focal point of the entire narrative, where recent three (tomato fever, monkeypox, and severe acute respiratory syndrome coronavirus 2) frightening viral pathogen outbreaks have occurred concurrently. India is currently in a transitional phasing where there is no scope to repeat the same mistakes that were made during the early stages of severe acute respiratory syndrome coronavirus 2 spreading. This flu needed a fair amount of attention or fret since it often affects children younger than 5, who do not have enough time to build up a strong immune system yet. Some believe that with a strong immune system, adults can protect themselves from this virus17. The Kerala Health Ministry has already launched a number of prophylactic measures and warning campaigns to combat tomato flu18. In light of this, Kerala has issued a warning over the tomato flu spread in the Mysuru and Kodagu districts19. Health professionals regularly check the age group of vulnerable children for new viral infections. Even though there are no travel restrictions in place, district health officials have been encouraged to boost border surveillance to halt the spread of tomato flu cases to Karnataka and Tamil Nadu (Fig. 1a)20. At all checkpoints that border Kerala, the governments of Tamil Nadu and Karnataka have increased their health monitoring. The core problem with tomato flu is the lack of scientific clarity, the unavailability of scientific evidence, or the paucity of studies to identify the underlying causative agent and its pathophysiology. So, we need research-based evidence right now to fully understand this flu and take the right steps to stop this outbreak from becoming a pandemic. In some instances, the symptoms of this fever (like, runny nose, fever, body pain, headache, etc.) mimic those of people infected with COVID-19 or HFMD rather closely (Fig. 1b). Therefore, by strictly adhering to the declared guidelines of the Indian government’s COVID related to every protocol, this outbreak may be stopped. During the early stages of the COVID-19 pandemic, health officials in every state of India took quick, voluntary steps. For example, they increased the number of medical facilities, did mass tests, made sure that people who were sick were properly compensated, and held social awareness camps, among other things. Now, in this timeframe, such significant efforts were required from every administrative official, health professional, and normal person to successfully combat tomato fever.Figure 1: (a) Geographical sites where occurrences of tomato fever have been officially announced in India. India’s map was generated and edited in Mapchart.net web platform. (b) Tomato fever symptoms and signs are represented schematically. Some suggested safety steps for preventing the spread of this infection.Ethical approval Not applicable. Sources of funding None. Authors’ contribution S.S. contributed in conceptualization, data curation, writing – original draft, review and editing. J.B. contributed in writing – original draft, review and editing, software. S.D. contributed in data curation, writing – original draft, review and editing. R.A. contributed in writing – original draft, writing – review and editing. S.K.D. contributed in conceptualization, supervision, data curation, writing – original draft, review and editing. All authors critically reviewed and approved the final version of the manuscript. Conflicts of interest disclosure The authors declare that they have no financial conflicts of interest with regard to the consent of this report. Research registration unique identifying number (UIN) None. Guarantor Sandeep Kumar Dash. Provenance and peer review Not commissioned, internally peer-reviewed. Acknowledgments The opportunity to work in the Department of Physiology at the University of Gour Banga is much appreciated by the authors.